Device and method for projecting an image

ABSTRACT

The present invention relates to a method of projecting a portion of an image, which is to be projected on to a display area, with improved brightness, comprising the steps of configuring a projector such that it projects over a portion of the display area, modifying a signal which defines the pixels of the image, to provide a signal which defines pixels of a portion of the image. The present invention further relates to a corresponding device.

FIELD OF THE INVENTION

The present invention concerns a device and method for projecting animage, or part of an image, and in particular, but not exclusively, adevice and method for projecting an image, or part of an image, withimproved brightness.

DESCRIPTION OF RELATED ART

A MEMS micro-mirror device is a device that contains anMicro-Electrical-Mechanical-System that comprises a reflective member.The MEMS may comprise a cylindrical, rectangular, elliptical or squaremicro-mirror that is adapted to move and to deflect light over time. Themicro-mirror is usually connected by torsion arms to a fixed part andcan tilt and oscillate along one or two axis. Different actuationprinciples can be used, including electrostatic, thermal,electro-magnetic or piezo-electric. MEMS micro-mirror devices are knownin which the area of these micro-mirrors are around a few mm². In thiscase, the dimensions of the MEMS device, comprising the packaging, isaround ten mm². This device is usually made of silicon, and can beencapsulated in a package that can include the driving actuationelectronics. Various optical components, such as for example lenses,beam combiner, quarter-wave plates, beam splitter and laser chips, canalso be assembled with the packaged MEMS to build a complete system suchas, for example, a projection system.

A typical application of the MEMS micro-mirror devices is for projectionsystems. In a projection system, a 2-D image or a video can be displayedon a display surface; each pixel of the 2-D image or a video isgenerated by combining modulated red, green and blue and/or otherwavelength laser light sources, such as UV or IR, by means of, forexample, a beam combiner. The combined light from the modulated red,green and blue laser is emitted from the beam combiner as a beam oflight. The beam of light emitted from the beam combiner comprisespulses, and each pulse will correspond to a pixel of the 2-D image or avideo. A MEMS micro-mirror device directs the beam of light to a MEMSmicro-mirror which is oscillated to scan the beam of light in a zig-zag,unidirectional or bidirectional raster (interlaced or not interlaced) orlissajou pattern across the display surface so that the 2-D image, or avideo, is displayed on the display surface, pixel-by-pixel. The MEMSmicro-mirror within the MEMS micro-mirror device will continuouslyoscillate to scan light, for example, from left to right and from top tobottom so that each pixel of the 2-D image or a video which is projectedonto the display surface, is continuously refreshed. The speed ofoscillation of the MEMS micro-mirror is such that a complete 2-D imageor a video is visible on the display surface.

A MEMS micro-mirror may be configured to be able to oscillate along oneaxis. Therefore, in order to display a 2-D image on a display surface, aprojection system will require a first MEMS micro-mirror to scan lightalong the horizontal and a second MEMS micro-mirror to scan light alongthe vertical. The first and the second MEMS micro-mirrors are preferablyprecisely positioned such that the oscillatory axes are orthogonal.

During operation, the micro-mirror of the first MEMS micro-mirrorreceives light from the beam combiner and deflects the light to thesecond MEMS micro-mirror. The second MEMS micro-mirror will in turndeflect the light to the display surface where it will appear as pixelsof an image. The first MEMS micro-mirror will oscillate about itsoscillatory axis to scan the light along the horizontal, therebydisplaying the first row of pixels on the display surface, pixel bypixel. When the first row of pixels have been projected onto the displaysurface, the second MEMS micro-mirror will oscillate about itsoscillatory axis so that light received from the first MEMS micro-mirroris directed towards the next row where pixels are to be displayed. Thefirst MEMS micro-mirror will then oscillate to scan the light along thehorizontal to display the next row of pixels. The process is continuousso that a complete image is visible on the display surface. It is alsopossible that both the first and second MEMS micro-mirrors oscillatesimultaneously, to scan light in a zig-zag, or so-called raster,direction across the display surface.

Typically projection systems comprise a MEMS micro-mirror device whichcomprises a single 2-D MEMS micro-mirror which can oscillate along twoorthogonal oscillation axes. During operation, the single 2-D MEMSmicro-mirror receives modulated light from the beam combiner anddeflects the light to a display surface where it will appear as a pixel.The single 2-D MEMS micro-mirror will oscillate along a firstoscillation axis to scan the light along the horizontal, therebydisplaying the first row of pixels on the display surface. When thefirst row of pixels are have been projected onto the display surface,the single 2-D MEMS micro-mirror oscillates about a second oscillationaxis (which is orthogonal to the first oscillation axis) so that lightreceived from the beam combiner is directed towards the next row wherepixels are to be displayed. The single 2-D MEMS micro-mirror will thenoscillate along the first oscillation axis to scan the light from thebeam combiner along the horizontal thereby displaying the next row ofpixels on the display surface. Preferably, both the first and secondMEMS micro-mirrors oscillate simultaneously, to scan light in a zig-zag,or so-called raster, direction across the display surface. The processis continuous so that a complete image is visible on the displaysurface. It is also possible that the 2-D MEMS micro-mirror oscillatesabout both the first and second oscillation axis simultaneously. Theadvantage of using a single 2-D MEMS micro-mirror which can oscillatealong two orthogonal oscillation axes, is that only a singlemicro-mirror is required to display a 2-D image on a display surface.

Existing projection systems typically project images over the whole areaof a display surface such as a projection screen. The light projectedfrom the projection system is thus spread over the whole displaysurface. For large display surfaces the brightness of the projectedimage is deceased as the light is spread over the whole display surface.

Of course light projected from the projection system can be concentratedto provide a brighter image; but focusing the light results in a smallerversion of the projected image.

Often, an object in an image (i.e. a pictogram) to be projected willonly form part of the whole image; the remaining parts of the imagebeing blank, for example an image of a person with a black background.In this example the pictogram of the person only forms part of the wholeimage, with the black background forming the remaining parts of theimage. A projection system will project the whole image, some of theprojected light being used to project the black background part of theimage. Thus, existing projection systems have inefficient use of light.

For a given projection system, which provides uniform image brightness,the brightness of the projected whole image (B) is given by thefollowing equation:

B=T*(P/S) wherein B brightness of the projected whole image; T is thetotal brightness of the light projected by the projection system; and Pis the area size occupied by the pictogram in the whole image, and S isthe area size of the whole image.

As only part of the total brightness of the light projected by theprojection system is used to project the pictogram of an image, thebrightness of the projected pictogram will not be optimum.

It is an aim of the present invention to mitigate, or obviate, at leastsome of the above-mentioned disadvantages.

BRIEF SUMMARY OF THE INVENTION

According to the invention, these aims are achieved by means of a methodof projecting a portion of an image, which is to be projected on to adisplay area, with improved brightness, comprising the steps of,configuring a projector such that it projects over a portion of thedisplay area, modifying a signal which defines the pixels of the image,to provide a signal which defines pixels of a portion of the image.

The display area may be defined by any suitable means. The display areamay be configured to absorb the UV light and re-emmit visible light; forexample the display area may comprise a film, configured to absorb theUV light and re-emmit visible light. The display area may be defined bya portion of or all of a windshield, or windscreen. For example, thedisplay area may be a windscreen of an automobile. The display area maybe defined by a portion of or all of a window. For example the displayarea may be defined by a display window in a shop. The display area maybe defined by an advertising board such as a billboard. The display areamay be any suitable projection screen. The method may further comprisethe step of provided a display area which is configured to absorb UVlight and re-emmit visible light; for example the display area maycomprise a film, configured to absorb the UV light and re-emmit visiblelight. The method may further comprise the step of provided a displayarea which is configured to absorb Infra-red light and re-emmit visiblelight; for example the display area may comprise a film, configured toabsorb the Infra-Red light and re-emmit visible light.

The portions of the image may be consecutive parts of an image i.e.parts which directly cooperate. Alternatively the portions of image maynot be in direct cooperation e.g. the portions may be separate portionswhich do not touch each other. Preferably a portion of the image isdefined as the smallest rectangle around a pictogram in the image.Preferably the portions are rectangles.

The method may comprise the steps of, configuring a projector such thatit projects consecutively over one or more other portions of the displayarea; modifying a signal which defines the pixels of the image toprovide a one or more signals each of which defines pixels of one ormore other portions of the image.

The step of configuring a projector such that it projects over a portionof the display area, may comprise the step of modifying the amplitude ofoscillations of a first mirror which oscillates to scan light.

The step of configuring a projector such that it projects over a portionof the display area, may further comprise the step of modifying theamplitude of oscillations of a second mirror which oscillates to scanlight.

The method may further comprise the step of providing an off-set to oneor more mirrors which can oscillate to scan light over some or all of asurface. The surface may define the display area. The method may furthercomprise the step of providing an off-set to one or more mirrors whichcan oscillate to scan light over some or all of the display area.

The method may further comprise the step of providing an off-set to oneor more actuation signals which is/are configured to actuate oscillationof one or more mirrors which can oscillate to scan light over some orall of a surface. The surface may define the display area

The method may comprise the step of providing a physical offset to oneor more mirrors which can oscillate to scan light over some or all of asurface. The surface may define the display area. The step of providinga physical offset may comprise the step of providing a holder on which amirror can be mounted and tilting the holder such that a mirror mountedon the holder is provided with a physical offset. The step of providinga physical offset may comprise the step of providing a frame around oneor more mirrors and adjusting this position of the frame using at leastone of a magnetic, electrostatic, thermal, or piezo actuator, holder toprovide the physical offset. The frame may be a silicon frame.

The one or more mirrors may comprise a first mirror and second mirror,wherein the first mirror oscillates at a faster rate than the secondmirror. The first mirror may oscillate to scan light along thehorizontal. The second mirror may oscillate to scan light along thevertical.

The method may comprise the step of providing an off-set to an actuationsignals which actuates oscillation of the second mirror and providing aphysical offset to the first mirror.

The method may further comprise the step of consecutively providing aplurality of off-sets to an actuation signal which is configured toactuate oscillation of a mirror which can oscillate to scan light oversome or all of a surface.

The method may further comprise the adjusting the two or more signalssuch that the two or more different portions of the image have equalbrightness. The method may comprise the step of adjusting the power inone of the two or more signals such that the two or more differentportions of the image have equal brightness. The method may comprise thestep of adjusting the power of one or more lasers such that the two ormore different portions of the image have equal brightness. The methodmay comprise the step of adjusting a laser power signal. The method maycomprise the step of reducing the power in one of the two or moresignals, or dimming one of the two or more signals, such that the two ormore different portions of the image have equal brightness. The methodmay comprise the step of reducing the power of one or more lasers suchthat the two or more different portions of the image have equalbrightness. The method may comprise the step of reducing a laser powersignal.

The method may further comprise the step of configuring the projectorsuch that the two or more different portions of the image are of equalsize when projected.

The method may further comprise the steps of, configuring the projectorsuch that it projects consecutively over one or more other portions of adisplay area; modifying the signal which defines the pixels of the imageto provide a two or more signals each of which defines pixels of two ormore different portions of the image.

According to the present invention there is provided a method ofprojecting an image with improved brightness, the method comprising thesteps of, configuring a projector such that it projects consecutivelyover one or more other portions of a display area; modifying a signalwhich defines the pixels of the image to provide a two or more signalseach of which defines pixels of two or more different portions of theimage.

According to a further aspect of the present invention there is provideda device which is operable to project an image over a display area, thedevice comprising, a means for configuring the device such that itprojects over a portion of the display area, a means for modifying asignal which defines the pixels of an image, to provide a signal whichdefines pixels of a portion of the image, such that the portion of theimage can be projected, with an improved brightness, on the portion ofthe display area.

The device may further comprise, a means for configuring the device suchthat it projects consecutively over one or more other portions of thedisplay area; a means for modifying a signal which defines the pixels ofan image to provide a one or more other signals each of which definespixels of one or more other portions of the image.

The means for configuring the device such that it projects consecutivelyover one or more other portions of the display area, may comprise ameans for modifying the amplitude of oscillations of a first mirrorwhich oscillates to scan light.

The means for configuring the device such that it projects consecutivelyover one or more other portions of the display area, may furthercomprise a means for modifying the amplitude of oscillations of a secondmirror which oscillates to scan light.

The first mirror may be configured to oscillate to scan light in ahorizontal direction and the second mirror may be configured tooscillate to scan light in a vertical direction. The second mirror maybe configured to oscillate to scan light in a horizontal direction andthe first mirror may be configured to oscillate to scan light in avertical direction.

The device may further comprise a means for providing an off-set to oneor more mirrors which can oscillate to scan light over some or all ofthe display area.

The device may further comprise a means for providing an off-set to anactuation signal which actuates oscillation of a mirror which oscillatesto scan light over the display area, such that an image is projected ata selected portion of the display area.

The device may comprise a means for adjusting the off-set.

The means for providing an off-set may further comprise a means forconsecutively providing a plurality of off-sets to an actuation signalwhich actuates oscillation of a mirror which oscillates to scan light,so that images can be consecutively projected to different portions ofthe display area.

The means for providing an off-set may further comprise a means forproviding a physical offset to one or more mirrors which can oscillateto scan light over some or all of the display area. The means forproviding a physical offset may comprise a holder on which a mirror canbe mounted wherein in the holder is configured such that it can betilted such that a mirror mounted on the holder is provided with aphysical offset. The means for providing a physical offset may comprisea frame around one or more mirrors wherein the frame is configured suchthat its position can be adjusted using at least one of a magnetic,electrostatic, thermal, or piezo actuator means, to provide a mirror inthe frame with a physical offset. The frame may be a silicon frame.

The device may comprise a first mirror and second mirror, wherein thefirst mirror oscillates at a faster rate than the second mirror. Thefirst mirror may oscillate to scan light along the horizontal. Thesecond mirror may oscillate to scan light along the vertical.

The device may comprise a means for providing an off-set to an actuationsignal which actuates oscillation of the second mirror and a means forproviding a physical offset to the first mirror.

The device may further comprise a means for consecutively providing aplurality of off-sets to an actuation signal which is configured toactuate oscillation of a mirror which can oscillate to scan light oversome or all of a surface.

The device may comprise a single UV laser which is configured to providea signal which defines pixels of the portion of the image.

The display area may be defined by any suitable means. The display areamay be configured to absorb UV light and re-emmit visible light; forexample the display area may comprise a film, configured to absorb theUV light and re-emmit visible light. The display area may be configuredto absorb Infra-red light and re-emmit visible light; for example thedisplay area may comprise a film, configured to absorb the Infra-Redlight and re-emmit visible light. The display area may be defined by aportion of or all of a windshield, or windscreen. For example, thedisplay area may be a windscreen of an automobile. The display area maybe defined by a portion of or all of a window. For example the displayarea may be defined by a display window in a shop. The display area maybe defined by an advertising board such as a billboard. The display areamay be any suitable projection screen.

The device may comprise a UV light source. The device may comprise asingle or multiple combined UV (Ultra-Violet) light sources. The deviceis arranged to cooperate with a surface which defines a display area,wherein the surface which defines the display area comprises a means toabsorb the light from the UV light source to display an image, and tore-emitted visible light. The means to absorb the light from the UVlight source to display an image, may comprise a film.

Additionally, or alternatively, the device may comprise an IR(Infra-Red) light source. The device may comprise a single or multipleInfra-Red light sources. The device may be arranged to cooperate with asurface which defines a display area, wherein the surface which definesthe display area comprises a means to absorb the light from theInfra-Red light source to display an image, and to re-emitted visiblelight. The means to absorb the light from the Infra-Red light source todisplay an image may comprise a film.

According to a further aspect of the present invention there is provideda surface which defines a display area on which an image can beprojected using any one of the above-mentioned devices, wherein thesurface further comprises a means to absorb the light from the UV lightsource provided in the device, to display an image, and to re-emittedvisible light. The means to absorb the light from the UV light source todisplay an image, may comprise a film. Alternatively, or additionally,the surface may comprise a means to absorb light from the Infra-Redlight source provided in the device, to display an image, and tore-emitted visible light. The means to absorb the light from a Infra-Redlight source provided in the device to display an image may comprise afilm. The surface which defines the display area may comprise at leastone of a window or advertising platform. The window may be a shopwindow. The advertising platform may be a billboard.

The device may further comprise a means for configuring the device suchthat it projects consecutively over two or more portions of a displayarea; and a means for modifying a signal which defines the pixels of theimage to provide two or more signals each of which defines pixels of twoor more different portions of the image, such that two or more differentportions of the image can be consecutively projected to the two or moreportions of a display area.

The device may further comprise, a means for configuring the device suchthat it projects consecutively over one or more other portions of thedisplay area; a means for modifying a signal which defines the pixels ofan image to provide a one or more other signals each of which definespixels of one or more other portions of the image.

The means for configuring the device such that it projects consecutivelyover one or more other portions of the display area, may comprise ameans for modifying the amplitude of oscillations of a first mirrorwhich oscillates to scan light.

The means for configuring the device such that it projects consecutivelyover one or more other portions of the display area, may furthercomprise a means for modifying the amplitude of oscillations of a secondmirror which oscillates to scan light.

The first mirror may be configured such that it can oscillate to scanlight in a horizontal direction and the second mirror is configured suchthat it can oscillate to scan light in a vertical direction.

The device may comprise a means for providing an off-set a mirror whichoscillates to scan light over the display area, such that an image isprojected at a selected portion of the display area. The device maycomprise a means for providing an off-set to an actuation signal whichactuates oscillation of a mirror which oscillates to scan light over thedisplay area, such that an image is projected at a selected portion ofthe display area

The means for providing an off-set may further comprise a means forconsecutively providing a plurality off-sets a mirror which oscillatesto scan light, so that images can be consecutively projected todifferent portions of the display area. The means for providing anoff-set may further comprise a means for consecutively providing aplurality off-sets to an actuation signal which actuate oscillation of amirror which oscillates to scan light, so that images can beconsecutively projected to different portions of the display area.

The device may further comprise a means for adjusting the two or moresignals such that the two or more different portions of the image haveequal brightness. The device may further comprise a means for adjustingthe power in one of the two or more signals such that the two or moredifferent portions of the image have equal brightness. The device mayfurther comprise a means for reducing the power in one of the two ormore signals, or dimming one of the two or more signals, such that thetwo or more different portions of the image have equal brightness.

The device may further comprise a means for configuring the projectorsuch that the two or more different portions of the image are of equalsize when projected.

According to the present invention there is provided a device forprojecting an image with improved brightness, the device comprising ameans for configuring the device such that it projects consecutivelyover one or more other portions of a display area; a means for modifyinga signal which defines the pixels of the image to provide two or moresignals each of which defines pixels of two or more different portionsof the image.

According to a further aspect of the present invention there is providedan automobile comprising one or more of any the aforementioned devices.The device may be configured in the automobile such that a windshield,windscreen, or any window of the automobile defines the display area.For example the rear window of an automobile may define the displayarea. For example, the front window of an automobile may define thedisplay area.

The windshield or windscreen may be configured to absorb UV light andre-emmit visible light; for example the windshield or windscreen maycomprise a film, configured to absorb the UV light and re-emmit visiblelight. The windshield or windscreen may be configured to absorbInfra-red light and re-emmit visible light; for example the windshieldor windscreen may comprise a film, configured to absorb the Infra-Redlight and re-emmit visible light.

According to a further aspect of the present invention there is provideda projection system comprising any one of the aforementioned devices,coupled with one or more sensor which is configured to sense a field ofview of a user, and a processing unit in operable communication with thedevice to configure the device to project a portion of an image of thefield of view sensed by the one or more sensor.

Wherein the projection system further comprises an eye tracking meanwhich tracks the direction in which a user is viewing.

The one or more sensor and processing unit may be configured to provideaugmented reality. For example, the sensor can sense and object in thefield of view, and then add to the projected image information or dataprocessed by the processing unit and in relation with the sensed object.This can be combined with an eye tracking system that modifies theposition of the added data/information in the projected image, accordingto the position of the eye of the user.

The one or more sensor may comprise at least one of a camera and/ordistance sensor for sensing the shape and/or the movement of an objectin a field of view. The distance sensor may also be configured to sensethe distance of an object in a field of view, from a user.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood with the aid of the descriptionof an embodiment given by way of example only and illustrated by thefigures, in which:

FIG. 1 provides a perspective view of a device according to oneembodiment of the present invention;

FIG. 2 illustrates the effect of decreasing the amplitude ofoscillations MEMS micro-mirrors which are in the device of FIG. 1,

FIG. 3 illustrates the effect of modulating light which is provided by abeam combiner in the device of FIG. 1;

FIG. 4 illustrates the effect of decreasing the amplitude ofoscillations of a first MEMS micro-mirror in the device of FIG. 1;

FIG. 5 illustrates the effect of decreasing the amplitude ofoscillations of a second MEMS micro-mirror in the device of FIG. 1;

FIG. 6 illustrates the effect decreasing the amplitude of oscillationsof the first and second mirror and applying an offset to an actuationsignal which is used to actuate oscillation a first and second MEMSmicro-mirror in the device of FIG. 1;

FIG. 7 provides a perspective view of a device according to a furtherembodiment of the present invention.

DETAILED DESCRIPTION OF POSSIBLE EMBODIMENTS OF THE INVENTION

FIG. 1 shows a device 1 which projects an image 3 which is defined by aplurality of pixels (not shown) over a display area 2. In this examplethe display area 2 is defined by an automobile windscreen 2. The imageis projected over the whole area of the display area 2. It will beunderstood that the display area 2 could be defined by any othersuitable means, e.g. a shop window.

The image 3 comprises a plurality of pictograms 4, which in this examplecomprise a clock pictogram 21, a speed dial pictogram 22 and a trafficsign pictogram 23. It will be understood that the pictograms 4 couldtake any form. The remaining parts of the image 3 are blank parts 35,which comprise no pictographic data. The image 3 is selectively dividedinto a first part 3 a which comprises a plurality of pictograms 4 and asecond part 3 b which comprise no pictographic data. It will beunderstood that the image could be selectively divided into any numberof parts.

The device 1 comprises a first and second MEMS micro mirror 5, 7 whichoscillate to scan light from across the display area 2. The first MEMSmicro mirror 5 can oscillate about a first oscillation axis 8 and thesecond MEMS micro mirror 7 can oscillate about a second oscillation axis12. The first and second oscillation axes 8,12 are preferably arrangedorthogonal to each other. It will be understood that a single 2-D MEMSmicro mirror which oscillates about two orthogonal oscillation axes mayalternatively be provided.

The device 1 comprises a red 11, green 13 and blue 15 laser light sourceand/or any other laser wavelength such as IR and/or UV (not shown), anda beam combiner 17 which is in optical communication with each of thelight sources 11, 13, 15. Each pixel of the image 3 is generated bycombining modulated red 11, green 13 and blue 15 laser light sourcesand/or IR and/or UV laser(s) (not shown), by means of, for example, abeam combiner 17. The combined light from the modulated red, green andblue laser and/or IR and/or UV laser(s) (not shown) is emitted from thebeam combiner as a beam of light 19. The beam of light 19 emitted fromthe beam combiner 17 comprises pulses, and each pulse will correspond toa pixel of the image 3. Alternatively, instead of a red 11, green 13 andblue 15 laser light source and a beam combiner 17, the device 1 maycomprise a single or multiple UV light source or single or multipleInfra-Red light source (not shown). The automobile windscreen 2 whichdefines the display area 2 may be provided with a film which isconfigured to absorb the UV light or Infra-Red light which is providedby the UV light source or Infra-Red light source and re-emmit visiblelight (this is known as the stoke-shift effect). The UV light orInfra-red light is absorbed by the film to display an image on thewindscreen 2. It is also possible that the device has a plurality of UVlight sources and/or Infra-Red light sources (not shown). The pluralityof UV light sources and/or Infra-Red light sources may be operablycoupled to with a beam combiner, in order to increase the overall outputpower of the device and thus the overall brightness of the imagesprojected.

During operation, the first MEMS micro-mirror 5 receives light 19 fromthe beam combiner 17 and deflects the light to the second MEMSmicro-mirror 7. The second MEMS micro-mirror 7 will in turn deflect thelight to the display area 2 where it will appear as pixels of the image3. The first MEMS micro-mirror 5 will oscillate about its oscillatoryaxis 8 to scan the light 9 which is received from the beam combiner 17,along the horizontal, thereby displaying a first row of pixels on thedisplay area 2, pixel by pixel. When the first row of pixels has beenprojected onto the display area 2, the second MEMS micro-mirror 7 willoscillate about its oscillatory axis 12 so that light it received fromthe first MEMS micro-mirror is directed towards the next row wherepixels are to be displayed. The first MEMS micro-mirror 5 will thenoscillate to scan the light along the horizontal to display the next rowof pixels. The process is continuous so that a complete image 3 isvisible on the display area 2. The amplitudes of oscillation of thefirst and second MEMS micro mirrors 5, 7 are such that light 19 from thebeam combiner 17 is scanned across the whole area of the display area 2;thus the image 3 is projected onto the whole area of the display area 2.

It is also possible that both the first and second MEMS micro-mirrors 5,7 oscillate simultaneously, to scan light in a zig-zag or rasterdirection across the display area 2. It will also be understood that thedevice 1 may comprise a single 2D MEMS micro-mirror, which can oscillateabout two orthogonal oscillation axes, instead of the first and secondMEMS micro-mirrors 5, 7 which each oscillate about two orthogonaloscillation axes.

As discussed the image 3 comprises a plurality of pictograms 4, which inthis case comprise a clock pictogram 21, a speed dial pictogram 22 and atraffic sign time pictogram 23. The remaining parts of the image 3 arecomprising blank parts 35 which have no pictographic data. The image 3can thus be selectively divided into a first part 3 a which comprises aplurality of pictograms 4 and a second part 3 b which comprise nopictographic data. The light 19 provided by the beam combiner 17 is usedto display the whole image 3 i.e. both the first part 3 a and the secondpart 3 b; thus the light 19 provided by the beam combiner 17 is used todisplay the pictograms 4. The whole image 3 in FIG. 1 is sized suchthat, light 19 provided by the beam combiner 17 is only provided to thefirst and second oscillating MEMS micro-mirrors 5, 7 only over part ofthe oscillation of the first and second MEMS micro-mirrors 5, 7. Thus,the first and second MEMS micro-mirrors 5, 7 do not project light overtheir entire oscillation amplitude. Accordingly, the projection system'soperation is inefficient.

The present invention aims to provide a brighter image, or brighterpictograms 4, by using all, or at least most of, the light 19 providedby the beam combiner 17, to display the first part 3 a of the image 3.The present invention achieves this by reducing the area over which thedevice 1 projects and modifying the light 19 provided by the beamcombiner 17 such that it defines pixels of the first part 3 a of theimage 3 only. The result is that the pictograms 4 appear brighter, asthe light which would have been used to display the second part 3 b ofthe image, is now used to display the first part 3 a of the image.Furthermore, by adjusting the speed of oscillation of first and secondMEMS micro-mirrors 5, 7; modifying the light 19 provided by the beamcombiner 17; combined with reducing the area over which the device 1projects will ensure that the first part 3 a of the image can berefreshed more often. Alternatively, only the speed of one of the firstor second MEMS micro-mirrors 5, 7 is adjusted. Preferably, the speed ofthe slower oscillating mirror is adjusted.

According to the present invention, the device 1 is configured toproject over a portion of the display area 2. In this particularexample, this is achieved by adjusting the amplitude of oscillations ofboth the first and second MEMS micro-mirrors 5, 7. More specifically,the amplitude of oscillations of both the first and second MEMSmicro-mirrors 5, 7, are decreased. This can be achieved by decreasingthe amplitude of the actuation signal which actuates oscillation of thefirst and second MEMS micro-mirrors 5, 7. As the amplitude ofoscillations of both the first and second MEMS micro-mirrors 5, 7, isdecreased the light 19 from the beam combiner will be scanned over aportion of the display area 2, and not over the whole of the displayarea 2; thus the device 1 will project over a portion of the displayarea 2.

The result of decreasing the amplitude of oscillations of both the firstand second MEMS micro-mirrors 5, 7, is depicted in FIG. 2. Reducing theamplitude of oscillation of the first MEMS micro-mirror 5 will reducethe horizontal distance on the display area 2 over which the light 19 isscanned. Reducing the amplitude of oscillation of the second MEMSmicro-mirror 7 will reduce the vertical distance on the display area 2over which the light 19 is scanned. Thus, whole of the image 3 (firstpart 3 a and second part 3 b) is now projected over a portion 30 of thedisplay area 2. Thus, the whole image 3 will appear smaller than itsoriginal size (i.e. the size of the image 3 when it was projected overthe whole of the display area 2, as shown in FIG. 1).

The light 19 provided by the beam combiner 17 is then modulated suchthat the light 19 provided by the beam combiner 17 defines only pixelsfor the first part 3 a of the image 3. This modulation may be achievedusing digital processing circuits or optical signal processing circuits.Thus, all the light 19 provided by the beam combiner 17 now defines onlypixels for the first part 3 a of the image 3 which comprises thepictograms 4; the portion of the light 19 which would have been used toproject the second part 3 b of the image, is now used to project thefirst part 3 a so that more of the light 19 provided by the beamcombiner 17 is used to define pixels of the pictograms 4. As a resultthe pictograms 4 appear brighter.

The result of modulating the light 19 provided by the beam combiner 17is shown in FIG. 3. As shown in FIG. 3 the original size of the firstpart 3 a of the image is restored by modulating the light 19 provided bythe beam combiner 17. Thus, the first part 3 a of the image is projectedwith its original size, but with improved brightness.

FIGS. 2 and 3 illustrate the effects when the amplitude of oscillationsof both the first and second MEMS micro-mirrors 5, 7, are decreased. Itwill be understood that it is also possible that the amplitude ofoscillations of only one of the first or second MEMS micro-mirrors 5, 7is decreased.

FIG. 4, shows the effect when the amplitude of oscillations of the firstMEMS micro-mirror 5 only is decreased, and the light 19 provided by thebeam combiner 17 is modulated such that the light 19 provided by thebeam combiner 17 defines only pixels for the first part 3 a of the image3. Reducing the amplitude of oscillation of the first MEMS micro-mirror5 will reduce the horizontal distance on the display area 2 over whichthe light 19 is scanned; as the amplitude of oscillation of the secondMEMS micro-mirror 7 is not reduced the vertical distance on the displayarea 2 over which the light 19 is scanned remains unchanged (i.e. thewhole vertical length of the display area 2). Thus, the first part 3 aof the image is projected on a side portion 40 of the display area 2

Likewise, FIG. 5, shows the effect when the amplitude of oscillations ofthe second MEMS micro-mirror 7 only is decreased, and the light 19provided by the beam combiner 17 is then modulated such that the light19 provided by the beam combiner 17 defines only pixels for the firstpart 3 a of the image 3. Reducing the amplitude of oscillation of thesecond MEMS micro-mirror 7 will reduce the vertical distance on thedisplay area 2 over which the light 19 is scanned; as the amplitude ofoscillation of the first MEMS micro-mirror 5 is not reduced thehorizontal distance on the display area 2 over which the light 19 isscanned remains unchanged (i.e. the whole horizontal height of thedisplay area 2). Thus, the first part 3 a of the image is projected onan end portion 50 of the display area 2.

Additionally, an offset may be applied to the oscillations of the firstand/or second MEMS micro-mirrors 5,7. This may be achieved by applyingan offset (e.g. DC offset) to an actuation signal which is used toactuate oscillation of the first and second MEMS micro-mirrors 5,7.Applying an offset to the oscillations of the first and/or second MEMSmicro-mirrors 5,7, will modify where in the display area 2 the firstpart 3 a of the image 3 is projected. FIG. 6 illustrates the effect ofapplying an offset to the actuation signal which is used to actuateoscillation of the first MEMS micro-mirror 5. Thus, FIG. 6 illustratethe effect decreasing the amplitude of oscillations of the first andsecond mirror, as previously described, in addition to applying anoffset to the actuation signal which is used to actuate oscillation ofthe first MEMS micro-mirror 5. As can be seen in FIG. 6, the position onthe display area 2 where the first part 3 a of the image 3 is projectedis now moved vertically; so that the first part 3 a of the image 3 isprojected at a new position 60 in the display area 2. It will beunderstood that, additionally or alternatively, an offset could beapplied to the actuation signal which is used to actuate oscillation ofthe second MEMS micro-mirror 7.

FIG. 7 illustrates a device 80 according to a further embodiment of thepresent invention. The device 80 has many of the same features of thedevice 1 shown in FIG. 1, and like features are awarded the samereference numerals. In this embodiment the image 3 to be projected bythe device 1 comprises a plurality of pictograms 4 which are located inboth the first part 3 a and the second part 3 b of the image 3. As withthe device 1, the device 80 is configured to project an image 3 over aportion 91 of the display area 2.

In the device 80, the amplitude of oscillations of both the first andsecond MEMS micro-mirrors 5, 7 is adjusted. More specifically, theamplitude of oscillations of both the first and second MEMSmicro-mirrors 5, 7, are decreased. This can be achieved by decreasingthe amplitude of the actuation signal which actuates oscillation of thefirst and second MEMS micro-mirrors 5, 7. As the amplitude ofoscillations of both the first and second MEMS micro-mirrors 5, 7, isdecreased the light 19 from the beam combiner 17 will be scanned over asmaller area of the display area 2, and not over the whole area of thedisplay area 2. As a result the image 3 will be reduced in size, butwill remain projected towards the middle of the display area 2.

The light 19 provided by the beam combiner 17 is modulated such that thelight 19 provided by the beam combiner 17 provides, consecutively, afirst light signal which defines only pixels for the first part 3 a ofthe image 3, followed by a second light signal which defines only pixelsfor the second part 3 b of the image 3. As the first and second lightsignals are provided consecutively, the full amount of light which isavailable from the beam combiner 17 is used to form the first lightsignal; likewise the full amount of light which is available from thebeam combiner 17 is used to form the second light signal.

The device 80 further comprises a means 36 for providing one or moreoffsets to an actuation signal which actuates oscillation of the secondMEMS micro-mirror 7 and/or for providing one or more offsets to anactuation signal which actuates oscillation of the first MEMSmicro-mirror 5. An offset could simply be a DC voltage or currentapplied to an actuation signal which actuates oscillation of a MEMSmicro-mirror 5,7; for example, instead of applying +/−2V around a 0Vaxis, to the MEMS micro-mirror 5,7, a +/−2V around 1V axis is applied.Alternatively offset may be a physical offset. In the present examplethe means 36 provides a first offset and second offset, consecutively,to an actuation signal which actuates oscillation of the second MEMSmicro-mirror 7, to ensure that device 80 projects over a first area 71of the display area 2, when the first light signal is provided by thebeam combiner 17, and to ensure that device 80 projects to a second area73 of the display area 2, when the second light signal is provided bythe beam combiner 17. The speed at which the first offset and secondoffset are consecutively applied to the actuation signal which actuatesoscillation of the to the second MEMS micro-mirror 7, is such that itwill appear to a viewer as if the first part 3 a and second part 3 b ofthe image 3 are simultaneously projected to the first and second areas71, 73 respectively of the display area 2; thus a complete image 3 willbe visible to the user. As the full amount of light which is availablefrom the beam combiner 17 to project the first part 3 a and second part3 b, consecutively, the image 3 will appear brighter.

It should be understood that the image 3 is not limited to having firstpart 3 a and a second part 3 b; an image 3 to be projected may bedivided into any number of parts, and the number of parts into which animage is divided may be selected by a user or electronically based onthe position and/or number of pictograms 4 in the image 3. For example,if the image 3 to be projected comprises four pictograms then the image3 may be divided into four parts. For example, the image may comprisefour parts, each of the four parts comprising a different pictogram 4 ora different set of pictograms. Thus, an image 3 may comprise any numberof parts and an image 3 may have any number of pictograms 4. It shouldbe understood that the four parts may be separate parts of the image 3which do not directly cooperate with one another in the image;Preferably a parts of the image are defined as a plurality ofrectangles; wherein the rectangles are the smallest rectangles aroundeach pictogram in the image.

Likewise, the light 19 provided by the beam combiner 17 may be modulatedto provide any number of light signals each of which define pixels ofany number of parts of an image 3. For example, an image 3 may comprisefour parts each of the four parts comprising a different pictogram 4;the light 19 provided by the beam combiner 17 may be modulated toprovide, a first light signal which defines only pixels for a first partof the image 3, followed by a second light signal which defines onlypixels for the second part of the image 3; followed by a third lightsignal which defines only pixels for a third part of the image 3;followed by a fourth light signal which defines only pixels for a fourthpart of the image 3 etc.

A plurality of offsets may be consecutively applied to the actuationsignals which actuates oscillation of the each of the first and secondMEMS micro-mirrors 5,7. Typically the number of offsets will correspondto the number of parts into which the image 3 is divided. For example,if an image 3 is divided into four parts, four different offsets may beapplied to each of the actuation signals which actuate oscillation ofthe each of the first and second MEMS micro-mirrors 5, 7, such that eachof the four parts of the image 3 are projected to four different areasof the display area 2 e.g. such that each of the four parts of the image3 are projected to each of the four corners of the display area 2.Preferably, the speed at which the offsets are applied to the actuationsignals such that it will appear to a viewer as though that the fourparts of the image 3 are projected simultaneously.

Various modifications and variations to the described embodiments of theinvention will be apparent to those skilled in the art without departingfrom the scope of the invention as defined in the appended claims.Although the invention has been described in connection with specificpreferred embodiments, it should be understood that the invention asclaimed should not be unduly limited to such specific embodiment

1. A method of projecting a portion of an image, which is to beprojected on to a display area, with improved brightness, comprising thesteps of, configuring a projector such that it projects over a portionof the display area, and modifying a signal which defines the pixels ofthe image, to provide a signal which defines pixels of a portion of theimage.
 2. A method according to claim 1 wherein the method comprises thesteps of, configuring a projector such that it projects consecutivelyover one or more other portions of the display area; and modifying asignal which defines the pixels of the image to provide a one or moresignals each of which defines pixels of one or more other portions ofthe image.
 3. A method according to claim 1, wherein the step ofconfiguring a projector such that it projects over a portion of thedisplay area, comprises the step of modifying the amplitude ofoscillations of a first mirror which oscillates to scan light.
 4. Amethod according to any one of claim 1, wherein the step of configuringa projector such that it projects over a portion of the display area,comprises the step of modifying the amplitude of oscillations of asecond mirror which oscillates to scan light.
 5. A method according toclaim 1, further comprising the step of providing an one or moreoff-sets to one or more mirrors which can oscillate to scan light oversome or all of a surface.
 6. A device which is operable to project animage over a display area, the device comprising, a means forconfiguring the device such that it projects over a portion of thedisplay area, and a means for modifying a signal which defines thepixels of an image, to provide a signal which defines pixels of aportion of the image, such that the portion of the image can beprojected, with an improved brightness, on the portion of the displayarea.
 7. The device according to claim 6 further comprising, a means forconfiguring the device such that it projects consecutively over one ormore other portions of the display area; and a means for modifying asignal which defines the pixels of an image to provide a one or moreother signals each of which defines pixels of one or more other portionsof the image.
 8. The device according to claim 6, wherein the means forconfiguring the device such that it projects consecutively over one ormore other portions of the display area, comprises a means for modifyingthe amplitude of oscillations of a first mirror which oscillates to scanlight.
 9. The device according to claim 8, wherein means for configuringthe device such that it projects consecutively over one or more otherportions of the display area, further comprising a means for modifyingthe amplitude of oscillations of a second mirror which oscillates toscan light.
 10. The device according to claim 6, further comprising ameans for providing an off-set to a mirror which oscillates to scanlight over the display area, such that an image is projected at aselected portion of the display area.
 11. The device according to claim6, wherein the means for providing an off-set further comprises a meansfor consecutively providing a plurality off-sets to a mirror whichoscillates to scan light, so that images can be consecutively projectedto different portions of the display area.
 12. The device according toclaim 6, wherein the device comprises one or multiple UV light sources,and wherein the device is arranged to cooperate with a surface whichdefines a display area, wherein the surface which defines a display areacomprises a means to absorb the light from the UV light source todisplay an image, and to re-emitted visible light.
 13. The deviceaccording to claim 6, being provided in an automobile comprising andwherein the display area is defined by a windshield or windscreen of theautomobile.
 14. The device according to claim 6, being provided in aprojection system, the projection system comprising, the device beingcoupled with one or more sensor which is configured to sense a field ofview of a user, and a processing unit in operable communication with thedevice to configure the device to project a portion of an image of thefield of view sensed by the one or more sensor.
 15. A method ofprojecting an image with improved brightness, the method comprising thesteps of, configuring a projector such that it projects consecutivelyover one or more other portions of a display area; and modifying asignal which defines the pixels of the image to provide a two or moresignals each of which defines pixels of two or more different portionsof the image.